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While the occasional snapshot that includes the sun is generally safe, there are certainly combinations of lens and duration that can damage an image sensor if the sun or other sufficiently bright light source is present.

Are there industry standards or specifications for some minimum safe conditions of light exposure at the image sensor's surface? I'm asking about a spec that relates to the intensity at the surface of the sensor, so I'd expect that "industry" refers to sensor manufacturers.

Loosely speaking: is there some minimal, established test condition that most sensors can reliably survive without damage?

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    It's pretty much impossible to definitively prove something doesn't exist. But I've never seen or heard of such a standard or specifications. – Michael C May 15 '16 at 2:39
  • @MichaelClark I appreciate your point! I'm not sure exactly where to even look. I was hoping to at least find something roughly equivalent to semi.org or jedec.org or itu.int, but for semiconductor image sensors as a starting point for a search. – uhoh May 15 '16 at 7:02
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    Because this depends on wavelength and exposure time (and possibly temperature and whether/how the sensor is operating at the time) this would be very hard to specify. It's also much higher than the maximum useful intensity due to sensor saturation. That said I do think I've seen something for a sony CCD sensor I used years ago. If I can remember any details I'll try to find it. – Chris H May 15 '16 at 7:16
  • @ChrisH yep that's for sure. Still, in manufacturing, standardized tests are often better than nothing at all. It can at least demonstrates a minimal effort, and help reject batches that maybe - just as a hypothetical example for illustration purposes - used a color filter material with a softening point lower than normal. However these tests may not be typically exposed to the end user. – uhoh May 15 '16 at 13:32
  • I asked a similar question of Apple (Austin, Texas, US) engineers with regard to colour monitors. I had one of their largest (at the time) Cinema Display with 3 dead pixels that were driving me crazy due to their position. Although the display was under warrantee; it was within their acceptance specifications (16 pixels) and not something "fixable," per-se. – Stan May 15 '16 at 22:24
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The closest to a standard I've been able to find comes from looking at front-of-lens filters for solar photography - that is, filters for use with telescopes (or telephoto lenses) specifically for taking white light pictures of the sun.

For visual solar observation, the standard is ND5.0. Baader Planetarium also do an ND3.8 version for high magnification imaging use (NOT visual), and the Wikipedia entry for Neutral density filters has the following note:

Note: ND 3.8 is the correct value for solar CCD exposure without risk of electronic damage.

But doesn't have a citation to explain where the number comes from.

On the other hand, there is a clear conflict between this and everyday experience with non-DSLR digital cameras. It's not unusual to have the sun in shot - either intentionally, or while framing - and yet we don't get burnt out tracks across the sensor from doing this.

Part of the explanation may be due to consumer cameras having built in IR blocking filters for colour balance (Many astronomical CCDs don't). Another part may be that many point and shoot cameras use relatively small lenses - so they don't capture anywhere near as much heat and light as a telescope, which usually have objective lenses or mirrors of several inches in diameter.

Also, with conventional photography, at least for handheld shots, you're usually looking at durations of a few seconds at a time, often moving as you're framing the shot - so there's not normally much time for the heat to build up. If you contrast that with solar imaging, where you're normally tracking the sun for several minutes (or hours, sometimes), with a much larger objective lens / mirror (and so captures more light/heat), you can see why a filter becomes more important.

With a total solar eclipse coming up soon in the USA, it's probably worth adding a safety warning about filters for visual use. You only have one set of eyes so don't take chances - only use filters specifically designed for solar use. Don't try to improvise from exposed film, CDs or whatever. Visual performance is not a safe guide for performance at invisible IR / UV wavelengths. Proper solar filters are relatively inexpensive - a couple of dollars for something handheld that you can look through with the naked eye, or 20 - 30 dollars for a sheet of solar filter film, or you can get premade filters (The visual grade ND5.0 ones are fine to photograph through, too).

and as the wikipedia ND filter entry also notes:

Note: ND 5.0 is the minimum for direct eye solar observation without damage of retina. A further check must be performed for the particular filter used, checking on the spectrogram that also UV and IR are mitigated with the same value.

Purpose built solar filters are safe. Others are unknown, and not worth risking your eyesight over.

  • Very interesting analysis, thanks for the research! You make an excellent point, the IR filter will have a significant impact, although glass and especially plastic lenses will have some IR blocking as well. The red highlighted areas in the plot here are Watts/square meter/nanometer commons.wikimedia.org/wiki/File:Solar_Spectrum.png For the power passed, the color filter on each pixel will absorb very roughly 2/3 of the irradiance in the visible band - the things most likely to melt. Until we can find an actual industry spec, I'm going to accept this answer, thanks! – uhoh Apr 23 '17 at 0:46
  • The confusion in ND filter naming could get someone hurt here. An ND5.0 filter ( !!!THIS IS SEVENTEEN STOPS!!!) is a very different beast from a 5 stop ND filter or a 5x ND filter ! – rackandboneman Jan 16 at 13:24
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No there isn't a common industry standard to the best of my knowledge, no need, since the products are not designed to endure this. The durability depends on many factors like building materials, heat resistances, magnification, aperture, exposure time and light intensity etc. just to mention a few.

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    I disagree with your first sentence. I believe that point-and-shoot cameras are definitely designed so that if the sun is within the frame, they are not instantly destroyed. Point-and-shoots with LCDs do not have mechanical shutters, or if they do, they are open when the camera is in use. If you are composing a mid or long distance shot with the sun in the field of view, the sun is focused to a small spot on the sensor. Lay your camera down, pointing up, the sun is focused on the sensor for quite a while. Am I misunderstanding something, or are they in fact clearly engineered to endure this? – uhoh Feb 14 '17 at 23:51
  • Fair enough, if you can document it or provide a link, then I will change it accordingly? – Goat Feb 15 '17 at 15:04

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